Trayer Engineering Corporation

898 Pennsylvania Ave. San Francisco, CA 94107

800-377-1774 l sales@trayer.com

w w w . t r a y e r . c o m

ATS/PNP Uninterruptible Primary Power

Superior Power Quality

Zero-Cycle Interruption

5kV, 15kV, 25kV and 35kV Ratings

Padmount or Submersible

Drop in Replacement for

Air Insulated Switchgear

100% Welded Stainless Steel

Storm Hardened Design

Trayer Engineering’s Automatic Transfer Switch

( ATS)/ Primary Network Protector (PNP) is designed to

assure cost-effective and reliable service to critical and

sensitive loads requiring uninterruptible power delivery.

Under normal operating conditions, the spot network is

simultaneously supplied by two independent feeders. This

creates a very “stiff” power source that significantly reduces

levels of voltage sag, voltage flicker and other power quality

concerns. Should a fault be detected on either of the feeds,

a vacuum fault interrupter (VFI) isolates the load from the

fault while seamlessly providing uninterrupted power to the

load. When the fault condition is cleared, the unit

automatically reverts to its dual-feed operation.

Trayer ATS/PNP Switchgear are fully self-contained units

available in padmount or submersible designs. The units are

similar in configuration to conventional automatic transfer

switchgear (ATS). What distinguishes the Trayer ATS/ PNP

from a conventional ATS is the use of vacuum fault

interrupters instead of conventional load break switches and

the use of grid-protection relaying. The Trayer

ATS/PNP has two field selectable modes, PNP for

Network operation or ATS to operate as a conventional

ATS.

Trayer Engineering is the recognized leader in tailoring

equipment to the specific demands of customers.

Trayer switch- gear products are distinguished by their

rugged, fully sealed and welded 304 stainless steel

construction built for decades of trouble-free

operation. These units also feature the latest in

advanced electronic controls.

Trayer Engineering Corporation

898 Pennsylvania Ave. San Francisco, CA 94107

800-377-1774 l sales@trayer.com

w w w . t r a y e r . c o m

ATS/PNP Uninterruptible Primary Power

Spot Network Protection Power companies rely on networked systems to provide

uninterrupted power delivery to critical loads. Spot networks

are used to assure continuous power where interruptions

must be avoided. Examples include: sports venue illumination

where HID lighting restrike time can cause extended delays;

or, critical loads in hospitals and data centers where false

starts of generator sets are expensive and disruptive, and

critical urban loads.

Networked systems rely on relay protection to interrupt faults

and reconfigure the system so that power to the critical load

is not interrupted. Directional overcurrent relaying is used for

“spot network” locations utilizing dual feeders.

The Trayer ATS/PNP combines high-performance VFI

switchgear with integrated controls to create a completely

self-contained, automatic network protection system that is

ideal for primary spot networks. The ATS/PNP is compatible

with standard feeder configurations and does not require any

special sys- tem wiring, relaying or external communications.

In fact, the ATS/PNP can be used as a drop-in replacement

to upgrade from existing automatic transfer switchgear. An

ATS doesn’t begin a transfer operation until an outage

occurs, guaranteeing a temporary power interruption. With

the ATS/PNP, the critical load is never without power.

PNP Operation The connections to the ATS/PNP are similar to a standard

ATS that is connected to two sources so that the load can

be fed from either source. An ATS uses vacuum switches

and electronic controls to change to the alternate source

when a fault occurs on the primary feeder. In a ATS/PNP,

the vacuum switches are replaced with vacuum fault

interrupters and the two sources are tied together so that

the load is normally fed from both sources simultaneously.

The operation of the ATS/PNP is as follows:

Figure 1 illustrates a typical spot network configuration. Two

primary substations feed the ATS/PNP. These two sources

are tied together (networked) within the unit via two VFIs that

are normally closed. The load is now shared by the two

primary substations, A and B.

In Figure 2, feeder B experiences a fault. The ATS/PNP

control senses the fault in both magnitude and the change in

current direction (due to the contribution of fault current from

feeder A). The unit’s control then opens VFI B to prevent

feeder A from feeding the fault and thus isolating the fault

from the ATS/PNP. The substation B circuit breaker also

opens, isolating the faulted feeder section. The critical load

remains continuously supplied from feeder A and does not

experience an outage.

Figure 1: Standard Operating Configuration Figure 2: Fault Condition

Trayer Engineering Corporation

898 Pennsylvania Ave. San Francisco, CA 94107

800-377-1774 l sales@trayer.com

w w w . t r a y e r . c o m

Padmount and Submersible Switchgear

Trayer has been manufacturing switchgear for over 50 years.

Trayer designs are built with 304 stainless steel, eliminating

corrosion.

Padmount designs are available as either a single side

access or a double side access unit.

Trayer Padmount Features

Single or double-sided designs available

Single-sided design:

- allows full operation from one side

- allows operation next to a wall or fence Lower profile design options available

Compact designs reduce space required

to operate equipment

Built with SEL relays for auto transfer and over

current protection

Ideally suited as retrofit equipment for

existing switchgear

Versatile design allows customers to select the RTU

of choice for SCADA applications

Trayer Submersible Features

Trayer submersible switchgear, stand, and

motorized operators can be disassembled and

passed through manhole openings and

reconstructed inside the vault

Trayer offers a choice of motorized operators,

either linear actuators or rugged Motopaks

for submersible applications

Multiple stand options allow for top or side

facing bushings

Hot dipped galvanized or 304 stainless steel

stands are available

Round or

rectangular

footprints

available

Trayer Engineering Corporation

898 Pennsylvania Ave. San Francisco, CA 94107

800-377-1774 l sales@trayer.com

w w w . t r a y e r . c o m

The Trayer Way

With 50 years of industry experience in medium voltage

switching and fault interruption, Trayer has a sterling

reputation for designing and building the toughest and

smartest switchgear on the market. Trayer is a pioneer

in vacuum breaker technology and continues to lead

the industry with designs that meet the demands for

highly reliable electrical grids. Plus, Trayer gear is noted

for safety and ease-of-operation by linemen. That’s why

Trayer switchgear is specified by utilities around the globe.

By combining excellent engineering with high quality

manufacturing, backed up with a solid commitment to

customer service, you can depend on Trayer Switchgear to

perform for decade after decade.

Engineering Expertise. Using state-of-the-art CAD and

software tools, Trayer engineers can design and model

switchgear designs for plug-and-play replacement of industry

standard configurations.

Quality and Craftsmanship. Trayer’s advanced U.S.

manufacturing facility utilizes the latest in fabrication and

manufacturing technology. We take pride in the skill of our

craftsmen who are experts in electrical, welding, electrical

testing, and associated disciplines.

Customer Support. From the initial specification of

switchgear through delivery, Trayer sales engineers will assist

you through all stages of your switchgear project. From our

extensive library of designs we can customize switchgear

rapidly to your specific application.

Trayer ATS/PNP for Spot Networks Operating Ratings

EACH SOURCE BREAKER (VFI) 5/15 kV 25 kV 35 kV

BIL Across Open Contacts (kV) 95 125 150

BIL Phase-to-Phase (kV) 95 125 150

BIL Phase-to-Ground (Bushing Dependent) (kV) 95 125 150

Continuous Current (Bushing Dependent) (Amps) 200/600 200/600 200/600

Interrupting Capacity (Symmetrical Amps) 12,500 12,500 12,500

Trayer ATS/PNP Fault Current Guidelines

Fault current rating must be considered when specifying an ATS/PNP.

The ATS/ PNP tap protection shall be capable of interrupting the available tap fault current, calculated as:

Source 1 available fault current + Source 2 available fault current = Tap available fault current.

Refer to the following tables:

VFI Tap(s) 5/15kV 25kV 35kV

Maximum available Tap fault current 12.5kA 12.5kA 12.5kA

Specify Current Limiting fuses for Tap protection if available Tap fault current exceeds 12.5kA RMS:

CL fuse Tap(s) 5/15kV 25kV 35kV

Maximum available Tap fault current 50kA 50kA 50kA